Thesis project - Operation safety of dam spillways

Company Description

We have been electrifying industries, powering homes and transforming life through innovation and collaboration for more than 100 years. Empowered by our goal, we are determined to enable fossil free living. To succeed we, as one of Europe's leading energy companies, must be fossil-free ourselves.

But that’s not enough. That’s why we are looking beyond our own industry, to see where we can really make a difference.

Join us in our journey towards fossil freedom.

Job Description

Power Climate Smarter living - that’s our purpose. We are looking for the brightest students to make this happen. Together you will contribute to a fossil free future. You will have a unique position to contribute to our purpose. All we ask from you is to use your Superpowers and share your energy to help us achieve our goal.

The project is to be performed at Vattenfall R&D.

Thesis background/subject/assignment

The discharge capacity of the spillway is an issue that concerns the safety of a dam facility. In addition to structural stability, the spillway operation should also be free of undesirable negative air pressure, vibrations etc. As known, high-velocity spillway flow entrains air that is also transported by the flow. This might give rise to formation of air cavity with negative air pressure at such spillways as piano key weirs, labyrinth weirs and fuse gates featuring falling water jets. To understand the two-phase behhaviours is essential for spillway operation and potential countermeasures. As prototype air flows can not be correctly modelled in the laboratory, CFD plays a unique role in this context. This study is closely related to the ongoing upgrade projects by dam owners.

Thesis goal/purpose

One spillway type (piano key weirs, labyrinth weirs or fuse gates) is to be chosen with experimental data. The project aims to achieve the following goals. (a) To simulate overflow and two-phase patterns at different discharges. (b) To compare CFD results with experimental data. (c) To clarify the scale effects of laboratory models. (d) To suggest potential countermeasures and risk reduction.

This assignment is for one student or two.

Execution

With a previous laboratory model in the background, the study is executed with the help of CFD modeling with ANSYS FLUENT. The previous model tests will be reviewed. Representative flow cases are simulated so as to capture the worst and most unfavorable operation scenario that gives rise to damages. Potential countermeasures are also examined in the modeling.

For the students

• To get familiar with the ongoing dam-safety projects in the country
• To learn about hydraulic model tests
• To learn the fundamental knowledge of CFD
• To develop CFD skills for simulations of spillway flows

The project consists of the following aspects.

1. Background and literature review
2. Data collection (spillway geometry and flows)
3. Learning of CFD techniques
4. CFD model setup with experimental verification
5. CFD simulations, result analyses etc.
6. Report writing

Qualifications

We are looking for a student to join our journey towards a fossil free future. You are soon to be graduated from your academic studies. You also identify yourself with our principles: active, open, positive and safe.

• Education - proper background is university education in civil (hydraulic) engineering, engineering physics or similar disciplines.
• Scope - the project corresponds to a 30 hp diploma work.
• Very good command of written English is required.
• Strong interests in hydropower, dam safety and hydraulic engineering.
• The time of execution should be within four (4) months, accomplished before the end of 2025.

Additional Information

More information

• Start of assignment – January 2025 or by agreement
• Location – Älvkarleby, Stockholm or by agreement
• Application – a combined document with your CV (with complete contact information) and cover letter, explaining your interest for hydropower. University grades are also to be submitted in the application.
• Deadline – the deadline for application is 2024-12-08. Incoming applications are processed on a running basis and the vacancy is filled as long a suitable candidate is found (the announce is then removed). This is the reason why you should not wait to the deadline to send in your application.
• Contact person and supervisor at Vattenfall – James Yang, james.yang@vattenfall.com, phone 070-2723 200. Inquiry can be made by phone.

Diversity & inclusion - in everything we do

At Vattenfall we build on the fact that diverse teams can outperform homogeneous teams. But we can only unleash and leverage the power of diversity, if we make everybody feel included. Read more about our important work on diversity & inclusion https://careers.vattenfall.com/about-us/diversity-and-inclusion/